gdb/location.c

   1 /* Data structures and API for location specs in GDB.
   2    Copyright (C) 2013-2022 Free Software Foundation, Inc.
   3
   4    This file is part of GDB.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  18
  19 #include "defs.h"
  20 #include "gdbsupport/gdb_assert.h"
  21 #include "gdbsupport/gdb-checked-static-cast.h"
  22 #include "location.h"
  23 #include "symtab.h"
  24 #include "language.h"
  25 #include "linespec.h"
  26 #include "cli/cli-utils.h"
  27 #include "probe.h"
  28 #include "cp-support.h"
  29
  30 #include <ctype.h>
  31 #include <string.h>
  32
  33 static std::string
  34   explicit_to_string_internal (bool as_linespec,
  35                                const explicit_location_spec *explicit_loc);
  36
  37 /* Return a xstrdup of STR if not NULL, otherwise return NULL.  */
  38
  39 static char *
  40 maybe_xstrdup (const char *str)
  41 {
  42   return (str != nullptr ? xstrdup (str) : nullptr);
  43 }
  44
  45 probe_location_spec::probe_location_spec (std::string &&probe)
  46   : location_spec (PROBE_LOCATION_SPEC, std::move (probe))
  47 {
  48 }
  49
  50 location_spec_up
  51 probe_location_spec::clone () const
  52 {
  53   return location_spec_up (new probe_location_spec (*this));
  54 }
  55
  56 bool
  57 probe_location_spec::empty_p () const
  58 {
  59   return false;
  60 }
  61
  62 std::string probe_location_spec::compute_string () const
  63 {
  64   return std::move (m_as_string);
  65 }
  66
  67 /* A "normal" linespec.  */
  68 linespec_location_spec::linespec_location_spec
  69   (const char **linespec, symbol_name_match_type match_type_)
  70   : location_spec (LINESPEC_LOCATION_SPEC),
  71     match_type (match_type_)
  72 {
  73   if (*linespec != NULL)
  74     {
  75       const char *p;
  76       const char *orig = *linespec;
  77
  78       linespec_lex_to_end (linespec);
  79       p = remove_trailing_whitespace (orig, *linespec);
  80
  81       /* If there is no valid linespec then this will leave the
  82          spec_string as nullptr.  This behaviour is relied on in the
  83          breakpoint setting code, where spec_string being nullptr means
  84          to use the default breakpoint location.  */
  85       if ((p - orig) > 0)
  86         spec_string = savestring (orig, p - orig);
  87     }
  88 }
  89
  90 linespec_location_spec::~linespec_location_spec ()
  91 {
  92   xfree (spec_string);
  93 }
  94
  95 location_spec_up
  96 linespec_location_spec::clone () const
  97 {
  98   return location_spec_up (new linespec_location_spec (*this));
  99 }
 100
 101 bool
 102 linespec_location_spec::empty_p () const
 103 {
 104   return false;
 105 }
 106
 107 linespec_location_spec::linespec_location_spec
 108   (const linespec_location_spec &other)
 109   : location_spec (other),
 110     match_type (other.match_type),
 111     spec_string (maybe_xstrdup (other.spec_string))
 112 {
 113 }
 114
 115 std::string
 116 linespec_location_spec::compute_string () const
 117 {
 118   if (spec_string != nullptr)
 119     {
 120       if (match_type == symbol_name_match_type::FULL)
 121         return std::string ("-qualified ") + spec_string;
 122       else
 123         return spec_string;
 124     }
 125   return {};
 126 }
 127
 128 address_location_spec::address_location_spec (CORE_ADDR addr,
 129                                               const char *addr_string,
 130                                               int addr_string_len)
 131   : location_spec (ADDRESS_LOCATION_SPEC),
 132     address (addr)
 133 {
 134   if (addr_string != nullptr)
 135     m_as_string = std::string (addr_string, addr_string_len);
 136 }
 137
 138 location_spec_up
 139 address_location_spec::clone () const
 140 {
 141   return location_spec_up (new address_location_spec (*this));
 142 }
 143
 144 bool
 145 address_location_spec::empty_p () const
 146 {
 147   return false;
 148 }
 149
 150 address_location_spec::address_location_spec
 151   (const address_location_spec &other)
 152   : location_spec (other),
 153     address (other.address)
 154 {
 155 }
 156
 157 std::string
 158 address_location_spec::compute_string () const
 159 {
 160   const char *addr_string = core_addr_to_string (address);
 161   return std::string ("*") + addr_string;
 162 }
 163
 164 explicit_location_spec::explicit_location_spec ()
 165   : location_spec (EXPLICIT_LOCATION_SPEC)
 166 {
 167 }
 168
 169 explicit_location_spec::~explicit_location_spec ()
 170 {
 171   xfree (source_filename);
 172   xfree (function_name);
 173   xfree (label_name);
 174 }
 175
 176 explicit_location_spec::explicit_location_spec
 177   (const explicit_location_spec &other)
 178   : location_spec (other),
 179     source_filename (maybe_xstrdup (other.source_filename)),
 180     function_name (maybe_xstrdup (other.function_name)),
 181     func_name_match_type (other.func_name_match_type),
 182     label_name (maybe_xstrdup (other.label_name)),
 183     line_offset (other.line_offset)
 184 {
 185 }
 186
 187 location_spec_up
 188 explicit_location_spec::clone () const
 189 {
 190   return location_spec_up (new explicit_location_spec (*this));
 191 }
 192
 193 bool
 194 explicit_location_spec::empty_p () const
 195 {
 196   return (source_filename == nullptr
 197           && function_name == nullptr
 198           && label_name == nullptr
 199           && line_offset.sign == LINE_OFFSET_UNKNOWN);
 200 }
 201
 202 std::string
 203 explicit_location_spec::compute_string () const
 204 {
 205   return explicit_to_string_internal (false, this);
 206 }
 207
 208 /* See description in location.h.  */
 209
 210 location_spec_up
 211 new_linespec_location_spec (const char **linespec,
 212                             symbol_name_match_type match_type)
 213 {
 214   return location_spec_up (new linespec_location_spec (linespec,
 215                                                        match_type));
 216 }
 217
 218 /* See description in location.h.  */
 219
 220 const linespec_location_spec *
 221 as_linespec_location_spec (const location_spec *locspec)
 222 {
 223   gdb_assert (locspec->type () == LINESPEC_LOCATION_SPEC);
 224   return static_cast<const linespec_location_spec *> (locspec);
 225 }
 226
 227 /* See description in location.h.  */
 228
 229 location_spec_up
 230 new_address_location_spec (CORE_ADDR addr, const char *addr_string,
 231                            int addr_string_len)
 232 {
 233   return location_spec_up (new address_location_spec (addr, addr_string,
 234                                                       addr_string_len));
 235 }
 236
 237 /* See description in location.h.  */
 238
 239 const address_location_spec *
 240 as_address_location_spec (const location_spec *locspec)
 241 {
 242   gdb_assert (locspec->type () == ADDRESS_LOCATION_SPEC);
 243   return static_cast<const address_location_spec *> (locspec);
 244 }
 245
 246 /* See description in location.h.  */
 247
 248 location_spec_up
 249 new_probe_location_spec (std::string &&probe)
 250 {
 251   return location_spec_up (new probe_location_spec (std::move (probe)));
 252 }
 253
 254 /* See description in location.h.  */
 255
 256 const probe_location_spec *
 257 as_probe_location_spec (const location_spec *locspec)
 258 {
 259   gdb_assert (locspec->type () == PROBE_LOCATION_SPEC);
 260   return static_cast<const probe_location_spec *> (locspec);
 261 }
 262
 263 /* See description in location.h.  */
 264
 265 const explicit_location_spec *
 266 as_explicit_location_spec (const location_spec *locspec)
 267 {
 268   gdb_assert (locspec->type () == EXPLICIT_LOCATION_SPEC);
 269   return static_cast<const explicit_location_spec *> (locspec);
 270 }
 271
 272 /* See description in location.h.  */
 273
 274 explicit_location_spec *
 275 as_explicit_location_spec (location_spec *locspec)
 276 {
 277   gdb_assert (locspec->type () == EXPLICIT_LOCATION_SPEC);
 278   return static_cast<explicit_location_spec *> (locspec);
 279 }
 280
 281 /* Return a string representation of the explicit location spec in
 282    EXPLICIT_LOCSPEC.
 283
 284    AS_LINESPEC is true if this string should be a linespec.  Otherwise
 285    it will be output in explicit form.  */
 286
 287 static std::string
 288 explicit_to_string_internal (bool as_linespec,
 289                              const explicit_location_spec *explicit_loc)
 290 {
 291   bool need_space = false;
 292   char space = as_linespec ? ':' : ' ';
 293   string_file buf;
 294
 295   if (explicit_loc->source_filename != NULL)
 296     {
 297       if (!as_linespec)
 298         buf.puts ("-source ");
 299       buf.puts (explicit_loc->source_filename);
 300       need_space = true;
 301     }
 302
 303   if (explicit_loc->function_name != NULL)
 304     {
 305       if (need_space)
 306         buf.putc (space);
 307       if (explicit_loc->func_name_match_type == symbol_name_match_type::FULL)
 308         buf.puts ("-qualified ");
 309       if (!as_linespec)
 310         buf.puts ("-function ");
 311       buf.puts (explicit_loc->function_name);
 312       need_space = true;
 313     }
 314
 315   if (explicit_loc->label_name != NULL)
 316     {
 317       if (need_space)
 318         buf.putc (space);
 319       if (!as_linespec)
 320         buf.puts ("-label ");
 321       buf.puts (explicit_loc->label_name);
 322       need_space = true;
 323     }
 324
 325   if (explicit_loc->line_offset.sign != LINE_OFFSET_UNKNOWN)
 326     {
 327       if (need_space)
 328         buf.putc (space);
 329       if (!as_linespec)
 330         buf.puts ("-line ");
 331       buf.printf ("%s%d",
 332                   (explicit_loc->line_offset.sign == LINE_OFFSET_NONE ? ""
 333                    : (explicit_loc->line_offset.sign
 334                       == LINE_OFFSET_PLUS ? "+" : "-")),
 335                   explicit_loc->line_offset.offset);
 336     }
 337
 338   return buf.release ();
 339 }
 340
 341 /* See description in location.h.  */
 342
 343 std::string
 344 explicit_location_spec::to_linespec () const
 345 {
 346   return explicit_to_string_internal (true, this);
 347 }
 348
 349 /* Find an instance of the quote character C in the string S that is
 350    outside of all single- and double-quoted strings (i.e., any quoting
 351    other than C).  */
 352
 353 static const char *
 354 find_end_quote (const char *s, char end_quote_char)
 355 {
 356   /* zero if we're not in quotes;
 357      '"' if we're in a double-quoted string;
 358      '\'' if we're in a single-quoted string.  */
 359   char nested_quote_char = '\0';
 360
 361   for (const char *scan = s; *scan != '\0'; scan++)
 362     {
 363       if (nested_quote_char != '\0')
 364         {
 365           if (*scan == nested_quote_char)
 366             nested_quote_char = '\0';
 367           else if (scan[0] == '\\' && *(scan + 1) != '\0')
 368             scan++;
 369         }
 370       else if (*scan == end_quote_char && nested_quote_char == '\0')
 371         return scan;
 372       else if (*scan == '"' || *scan == '\'')
 373         nested_quote_char = *scan;
 374     }
 375
 376   return 0;
 377 }
 378
 379 /* A lexer for explicit location specs.  This function will advance
 380    INP past any strings that it lexes.  Returns a malloc'd copy of the
 381    lexed string or NULL if no lexing was done.  */
 382
 383 static gdb::unique_xmalloc_ptr<char>
 384 explicit_location_spec_lex_one (const char **inp,
 385                                 const struct language_defn *language,
 386                                 explicit_completion_info *completion_info)
 387 {
 388   const char *start = *inp;
 389
 390   if (*start == '\0')
 391     return NULL;
 392
 393   /* If quoted, skip to the ending quote.  */
 394   if (strchr (get_gdb_linespec_parser_quote_characters (), *start))
 395     {
 396       if (completion_info != NULL)
 397         completion_info->quoted_arg_start = start;
 398
 399       const char *end = find_end_quote (start + 1, *start);
 400
 401       if (end == NULL)
 402         {
 403           if (completion_info == NULL)
 404             error (_("Unmatched quote, %s."), start);
 405
 406           end = start + strlen (start);
 407           *inp = end;
 408           return gdb::unique_xmalloc_ptr<char> (savestring (start + 1,
 409                                                             *inp - start - 1));
 410         }
 411
 412       if (completion_info != NULL)
 413         completion_info->quoted_arg_end = end;
 414       *inp = end + 1;
 415       return gdb::unique_xmalloc_ptr<char> (savestring (start + 1,
 416                                                         *inp - start - 2));
 417     }
 418
 419   /* If the input starts with '-' or '+', the string ends with the next
 420      whitespace or comma.  */
 421   if (*start == '-' || *start == '+')
 422     {
 423       while (*inp[0] != '\0' && *inp[0] != ',' && !isspace (*inp[0]))
 424         ++(*inp);
 425     }
 426   else
 427     {
 428       /* Handle numbers first, stopping at the next whitespace or ','.  */
 429       while (isdigit (*inp[0]))
 430         ++(*inp);
 431       if (*inp[0] == '\0' || isspace (*inp[0]) || *inp[0] == ',')
 432         return gdb::unique_xmalloc_ptr<char> (savestring (start,
 433                                                           *inp - start));
 434
 435       /* Otherwise stop at the next occurrence of whitespace, '\0',
 436          keyword, or ','.  */
 437       *inp = start;
 438       while ((*inp)[0]
 439              && (*inp)[0] != ','
 440              && !(isspace ((*inp)[0])
 441                   || linespec_lexer_lex_keyword (&(*inp)[1])))
 442         {
 443           /* Special case: C++ operator,.  */
 444           if (language->la_language == language_cplus
 445               && startswith (*inp, CP_OPERATOR_STR))
 446             (*inp) += CP_OPERATOR_LEN;
 447           ++(*inp);
 448         }
 449     }
 450
 451   if (*inp - start > 0)
 452     return gdb::unique_xmalloc_ptr<char> (savestring (start, *inp - start));
 453
 454   return NULL;
 455 }
 456
 457 /* Return true if COMMA points past "operator".  START is the start of
 458    the line that COMMAND points to, hence when reading backwards, we
 459    must not read any character before START.  */
 460
 461 static bool
 462 is_cp_operator (const char *start, const char *comma)
 463 {
 464   if (comma != NULL
 465       && (comma - start) >= CP_OPERATOR_LEN)
 466     {
 467       const char *p = comma;
 468
 469       while (p > start && isspace (p[-1]))
 470         p--;
 471       if (p - start >= CP_OPERATOR_LEN)
 472         {
 473           p -= CP_OPERATOR_LEN;
 474           if (strncmp (p, CP_OPERATOR_STR, CP_OPERATOR_LEN) == 0
 475               && (p == start
 476                   || !(isalnum (p[-1]) || p[-1] == '_')))
 477             {
 478               return true;
 479             }
 480         }
 481     }
 482   return false;
 483 }
 484
 485 /* When scanning the input string looking for the next explicit
 486    location spec option/delimiter, we jump to the next option by looking
 487    for ",", and "-".  Such a character can also appear in C++ symbols
 488    like "operator," and "operator-".  So when we find such a
 489    character, we call this function to check if we found such a
 490    symbol, meaning we had a false positive for an option string.  In
 491    that case, we keep looking for the next delimiter, until we find
 492    one that is not a false positive, or we reach end of string.  FOUND
 493    is the character that scanning found (either '-' or ','), and START
 494    is the start of the line that FOUND points to, hence when reading
 495    backwards, we must not read any character before START.  Returns a
 496    pointer to the next non-false-positive delimiter character, or NULL
 497    if none was found.  */
 498
 499 static const char *
 500 skip_op_false_positives (const char *start, const char *found)
 501 {
 502   while (found != NULL && is_cp_operator (start, found))
 503     {
 504       if (found[0] == '-' && found[1] == '-')
 505         start = found + 2;
 506       else
 507         start = found + 1;
 508       found = find_toplevel_char (start, *found);
 509     }
 510
 511   return found;
 512 }
 513
 514 /* Assuming both FIRST and NEW_TOK point into the same string, return
 515    the pointer that is closer to the start of the string.  If FIRST is
 516    NULL, returns NEW_TOK.  If NEW_TOK is NULL, returns FIRST.  */
 517
 518 static const char *
 519 first_of (const char *first, const char *new_tok)
 520 {
 521   if (first == NULL)
 522     return new_tok;
 523   else if (new_tok != NULL && new_tok < first)
 524     return new_tok;
 525   else
 526     return first;
 527 }
 528
 529 /* A lexer for functions in explicit location specs.  This function will
 530    advance INP past a function until the next option, or until end of
 531    string.  Returns a malloc'd copy of the lexed string or NULL if no
 532    lexing was done.  */
 533
 534 static gdb::unique_xmalloc_ptr<char>
 535 explicit_location_spec_lex_one_function
 536   (const char **inp,
 537    const struct language_defn *language,
 538    explicit_completion_info *completion_info)
 539 {
 540   const char *start = *inp;
 541
 542   if (*start == '\0')
 543     return NULL;
 544
 545   /* If quoted, skip to the ending quote.  */
 546   if (strchr (get_gdb_linespec_parser_quote_characters (), *start))
 547     {
 548       char quote_char = *start;
 549
 550       /* If the input is not an Ada operator, skip to the matching
 551          closing quote and return the string.  */
 552       if (!(language->la_language == language_ada
 553             && quote_char == '\"' && is_ada_operator (start)))
 554         {
 555           if (completion_info != NULL)
 556             completion_info->quoted_arg_start = start;
 557
 558           const char *end = find_toplevel_char (start + 1, quote_char);
 559
 560           if (end == NULL)
 561             {
 562               if (completion_info == NULL)
 563                 error (_("Unmatched quote, %s."), start);
 564
 565               end = start + strlen (start);
 566               *inp = end;
 567               char *saved = savestring (start + 1, *inp - start - 1);
 568               return gdb::unique_xmalloc_ptr<char> (saved);
 569             }
 570
 571           if (completion_info != NULL)
 572             completion_info->quoted_arg_end = end;
 573           *inp = end + 1;
 574           char *saved = savestring (start + 1, *inp - start - 2);
 575           return gdb::unique_xmalloc_ptr<char> (saved);
 576         }
 577     }
 578
 579   const char *comma = find_toplevel_char (start, ',');
 580
 581   /* If we have "-function -myfunction", or perhaps better example,
 582      "-function -[BasicClass doIt]" (objc selector), treat
 583      "-myfunction" as the function name.  I.e., skip the first char if
 584      it is an hyphen.  Don't skip the first char always, because we
 585      may have C++ "operator<", and find_toplevel_char needs to see the
 586      'o' in that case.  */
 587   const char *hyphen
 588     = (*start == '-'
 589        ? find_toplevel_char (start + 1, '-')
 590        : find_toplevel_char (start, '-'));
 591
 592   /* Check for C++ "operator," and "operator-".  */
 593   comma = skip_op_false_positives (start, comma);
 594   hyphen = skip_op_false_positives (start, hyphen);
 595
 596   /* Pick the one that appears first.  */
 597   const char *end = first_of (hyphen, comma);
 598
 599   /* See if a linespec keyword appears first.  */
 600   const char *s = start;
 601   const char *ws = find_toplevel_char (start, ' ');
 602   while (ws != NULL && linespec_lexer_lex_keyword (ws + 1) == NULL)
 603     {
 604       s = ws + 1;
 605       ws = find_toplevel_char (s, ' ');
 606     }
 607   if (ws != NULL)
 608     end = first_of (end, ws + 1);
 609
 610   /* If we don't have any terminator, then take the whole string.  */
 611   if (end == NULL)
 612     end = start + strlen (start);
 613
 614   /* Trim whitespace at the end.  */
 615   while (end > start && end[-1] == ' ')
 616     end--;
 617
 618   *inp = end;
 619
 620   if (*inp - start > 0)
 621     return gdb::unique_xmalloc_ptr<char> (savestring (start, *inp - start));
 622
 623   return NULL;
 624 }
 625
 626 /* See description in location.h.  */
 627
 628 location_spec_up
 629 string_to_explicit_location_spec (const char **argp,
 630                                   const struct language_defn *language,
 631                                   explicit_completion_info *completion_info)
 632 {
 633   /* It is assumed that input beginning with '-' and a non-digit
 634      character is an explicit location.  "-p" is reserved, though,
 635      for probe locations.  */
 636   if (argp == NULL
 637       || *argp == NULL
 638       || *argp[0] != '-'
 639       || !isalpha ((*argp)[1])
 640       || ((*argp)[0] == '-' && (*argp)[1] == 'p'))
 641     return NULL;
 642
 643   std::unique_ptr<explicit_location_spec> locspec
 644     (new explicit_location_spec ());
 645
 646   /* Process option/argument pairs.  dprintf_command
 647      requires that processing stop on ','.  */
 648   while ((*argp)[0] != '\0' && (*argp)[0] != ',')
 649     {
 650       int len;
 651       const char *start;
 652
 653       /* Clear these on each iteration, since they should be filled
 654          with info about the last option.  */
 655       if (completion_info != NULL)
 656         {
 657           completion_info->quoted_arg_start = NULL;
 658           completion_info->quoted_arg_end = NULL;
 659         }
 660
 661       /* If *ARGP starts with a keyword, stop processing
 662          options.  */
 663       if (linespec_lexer_lex_keyword (*argp) != NULL)
 664         break;
 665
 666       /* Mark the start of the string in case we need to rewind.  */
 667       start = *argp;
 668
 669       if (completion_info != NULL)
 670         completion_info->last_option = start;
 671
 672       /* Get the option string.  */
 673       gdb::unique_xmalloc_ptr<char> opt
 674         = explicit_location_spec_lex_one (argp, language, NULL);
 675
 676       /* Use the length of the option to allow abbreviations.  */
 677       len = strlen (opt.get ());
 678
 679       /* Get the argument string.  */
 680       *argp = skip_spaces (*argp);
 681
 682       /* All options have a required argument.  Checking for this
 683          required argument is deferred until later.  */
 684       gdb::unique_xmalloc_ptr<char> oarg;
 685       /* True if we have an argument.  This is required because we'll
 686          move from OARG before checking whether we have an
 687          argument.  */
 688       bool have_oarg = false;
 689
 690       /* True if the option needs an argument.  */
 691       bool need_oarg = false;
 692
 693       /* Convenience to consistently set both OARG/HAVE_OARG from
 694          ARG.  */
 695       auto set_oarg = [&] (gdb::unique_xmalloc_ptr<char> arg)
 696         {
 697           if (completion_info != NULL)
 698             {
 699               /* We do this here because the set of options that take
 700                  arguments matches the set of explicit location
 701                  options.  */
 702               completion_info->saw_explicit_location_spec_option = true;
 703             }
 704           oarg = std::move (arg);
 705           have_oarg = oarg != NULL;
 706           need_oarg = true;
 707         };
 708
 709       if (strncmp (opt.get (), "-source", len) == 0)
 710         {
 711           set_oarg (explicit_location_spec_lex_one (argp, language,
 712                                                     completion_info));
 713           locspec->source_filename = oarg.release ();
 714         }
 715       else if (strncmp (opt.get (), "-function", len) == 0)
 716         {
 717           set_oarg (explicit_location_spec_lex_one_function (argp, language,
 718                                                              completion_info));
 719           locspec->function_name = oarg.release ();
 720         }
 721       else if (strncmp (opt.get (), "-qualified", len) == 0)
 722         {
 723           locspec->func_name_match_type = symbol_name_match_type::FULL;
 724         }
 725       else if (strncmp (opt.get (), "-line", len) == 0)
 726         {
 727           set_oarg (explicit_location_spec_lex_one (argp, language, NULL));
 728           *argp = skip_spaces (*argp);
 729           if (have_oarg)
 730             {
 731               locspec->line_offset = linespec_parse_line_offset (oarg.get ());
 732               continue;
 733             }
 734         }
 735       else if (strncmp (opt.get (), "-label", len) == 0)
 736         {
 737           set_oarg (explicit_location_spec_lex_one (argp, language,
 738                                                     completion_info));
 739           locspec->label_name = oarg.release ();
 740         }
 741       /* Only emit an "invalid argument" error for options
 742          that look like option strings.  */
 743       else if (opt.get ()[0] == '-' && !isdigit (opt.get ()[1]))
 744         {
 745           if (completion_info == NULL)
 746             error (_("invalid explicit location argument, \"%s\""), opt.get ());
 747         }
 748       else
 749         {
 750           /* End of the explicit location specification.
 751              Stop parsing and return whatever explicit location was
 752              parsed.  */
 753           *argp = start;
 754           break;
 755         }
 756
 757       *argp = skip_spaces (*argp);
 758
 759       /* It's a little lame to error after the fact, but in this
 760          case, it provides a much better user experience to issue
 761          the "invalid argument" error before any missing
 762          argument error.  */
 763       if (need_oarg && !have_oarg && completion_info == NULL)
 764         error (_("missing argument for \"%s\""), opt.get ());
 765     }
 766
 767   /* One special error check:  If a source filename was given
 768      without offset, function, or label, issue an error.  */
 769   if (locspec->source_filename != NULL
 770       && locspec->function_name == NULL
 771       && locspec->label_name == NULL
 772       && (locspec->line_offset.sign == LINE_OFFSET_UNKNOWN)
 773       && completion_info == NULL)
 774     {
 775       error (_("Source filename requires function, label, or "
 776                "line offset."));
 777     }
 778
 779   return location_spec_up (locspec.release ());
 780 }
 781
 782 /* See description in location.h.  */
 783
 784 location_spec_up
 785 string_to_location_spec_basic (const char **stringp,
 786                                const struct language_defn *language,
 787                                symbol_name_match_type match_type)
 788 {
 789   location_spec_up locspec;
 790   const char *cs;
 791
 792   /* Try the input as a probe spec.  */
 793   cs = *stringp;
 794   if (cs != NULL && probe_linespec_to_static_ops (&cs) != NULL)
 795     {
 796       locspec = new_probe_location_spec (*stringp);
 797       *stringp += strlen (*stringp);
 798     }
 799   else
 800     {
 801       /* Try an address location spec.  */
 802       if (*stringp != NULL && **stringp == '*')
 803         {
 804           const char *arg, *orig;
 805           CORE_ADDR addr;
 806
 807           orig = arg = *stringp;
 808           addr = linespec_expression_to_pc (&arg);
 809           locspec = new_address_location_spec (addr, orig, arg - orig);
 810           *stringp += arg - orig;
 811         }
 812       else
 813         {
 814           /* Everything else is a linespec.  */
 815           locspec = new_linespec_location_spec (stringp, match_type);
 816         }
 817     }
 818
 819   return locspec;
 820 }
 821
 822 /* See description in location.h.  */
 823
 824 location_spec_up
 825 string_to_location_spec (const char **stringp,
 826                          const struct language_defn *language,
 827                          symbol_name_match_type match_type)
 828 {
 829   const char *arg, *orig;
 830
 831   /* Try an explicit location spec.  */
 832   orig = arg = *stringp;
 833   location_spec_up locspec
 834     = string_to_explicit_location_spec (&arg, language, NULL);
 835   if (locspec != nullptr)
 836     {
 837       /* It was a valid explicit location.  Advance STRINGP to
 838          the end of input.  */
 839       *stringp += arg - orig;
 840
 841       /* If the user really specified a location spec, then we're
 842          done.  */
 843       if (!locspec->empty_p ())
 844         return locspec;
 845
 846       /* Otherwise, the user _only_ specified optional flags like
 847          "-qualified", otherwise string_to_explicit_location_spec
 848          would have thrown an error.  Save the flags for "basic"
 849          linespec parsing below and discard the explicit location
 850          spec.  */
 851       explicit_location_spec *xloc
 852         = gdb::checked_static_cast<explicit_location_spec *> (locspec.get ());
 853       match_type = xloc->func_name_match_type;
 854     }
 855
 856   /* Everything else is a "basic" linespec, address, or probe location
 857      spec.  */
 858   return string_to_location_spec_basic (stringp, language, match_type);
 859 }